He once famously fought with Earl Spencer to "defend the honour of his wife".

Guppy writes: "And then Mr Mair attacks the Mayor of London for agreeing, when in his mid twenties, to supply a friend – me – with the address of a News of the World journalist so that the journalist in question can be given the hiding which most of us secretly admit such people deserve."

Johnson has actually commended Mair for the interview saying he did a "splendid job".

This was on the same day Johnson's father, Stanley, attacked Mair for a "disgusting" job.